Dr. Mitchell W. Hecht is the physician-author of "Ask Dr. H," a weekly Q&A medical column distributed by McClatchy-Tribune News Service. Dr. Hecht's goal is to present medical information that is clear and interesting to non-medical people. Send questions to him at: "Ask Dr. H," P.O. Box 767787, Atlanta, GA 30076. Due to the large volume of mail received, personal replies are not possible.